Good-looking men have the most fertile sperm. Spanish scientists have discovered males with the healthiest, fastest sperm were also regarded as the most handsome by females.

Nearly 70 male faces were shown to 66 women, who rated their looks, while the men's semen quality was tested, said Evolution and Human Behaviour. The results showed the women's perception of attractiveness correlated to sperm mobility - but not amount of sperm.

A separate British study has found women with the most seductive voices had the most attractive faces.

Previous studies have found that people with more symmetrical facial features had a decreased chance of suffering ill health.